There is a method for increasing a data area into which user data is written in a magnetic disc apparatus by which a servo pattern is divided into a plurality of zones from the inner periphery to outer periphery of a magnetic disc and the write frequency (reference frequency) of the servo pattern in the outer periphery zone is higher than that in the inner periphery zone (zone servo method).
In the zone servo method, an invalid area of a predetermined width into which no user data is written is provided near the zone servo boundary to ensure that the servo patterns can be reliably changed between the zones.